Foamed reaction product of a resole with a sulfonated novolac

ABSTRACT

Phenol-formaldehyde resins, which are principally intended for the production of resin foams for use as insulating materials, in particular fire-resistant foams, are produced by reacting a sulphonated novolac resin, which has been condensed from at least one phenol and formaldehyde and subsequently sulphonated, with a resole resin. The novolac resin may be condensed from 1 mole of the phenol or phenols and between 0.3 and 1.0 moles formaldehyde in the presence of an organic acid, such as oxalic acid, and subsequently sulphonated with 0.1 to 1.5 moles 98% sulphuric acid at a temperature not exceeding 150*C. The resole resin may be condensed from 1 mole of a phenol or phenols and 1 to 3 moles formaldehyde in the presence of an alkaline catalyst. An aqueous dispersion of the resole resin is reacted with the sulphonated novolac resin, the viscosities of the two reactants being adjusted to be of the same order of magnitude, e.g. by diluting the sulphonation product with water. A surfactant and a foaming agent are added to the reaction mixture to cause foam formation.

United States Patent 11 1 Crook et al.

1451 Mar. 11, 1975 FOAMED REACTION PRODUCT OF A RESOLE WITH A SULFONATED NOVOLAC [75] Inventors: Peter John Crook, Billinge; Stephen Philip Riley, Saint Helens, both of England [73] Assignee: Pilkington Brothers Limited,

Liverpool, England [22] Filed: July 28,1972

211 Appl.No.:275,999

[30] Foreign Application Priority Data July 30, 1971 Great Britain 36015/71 [52] US. Cl. 260/25 F, 260/49, 260/57 A,

[51] Int. Cl C08g 53/08, C08j 1/26 [58] Field of Search 260/838, 2.5 F, 49

[56] References Cited UNITED STATES PATENTS 2.179,03s 11 1939 Guthke 260/838 3.207,652 9/1965 Shannon 260/25 F 3.389094 6/1968 DAlesandro 260/25 F 3,511,789 5/1970 Shannon et a1 260/25 F Primary Examiner-Morton Foelak Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT Phenol-formaldehyde resins, which are principally intended for the production of resin foams for use as insulating materials, in particular fire-resistant foams, are produced by reacting a sulphonated novolac resin. which has been condensed from at least one phenol and formaldehyde and subsequently sulphonated, with a resole resin. The novolac resin may be condensed from 1 mole of the phenol or phenols and between 0.3 and 1.0 moles formaldehyde in the presence of an or ganic acid, such as oxalic acid, and subsequently sulphonated with 0.1 to 1.5 moles 98% sulphuric acid at a temperature not exceeding 150C. The resole resin may be condensed from 1 mole of a phenol or phenols and l to 3 moles formaldehyde in the presence of an alkaline catalyst. An aqueous dispersion of the resole resin is reacted with the sulphonated novolac resin, the viscosities of the two reactants being adjusted to be of the same order of magnitude, e.g. by diluting the sulphonation product with water. A surfactant and a foaming agent are added to the reaction mixture to cause foam formation.

37 Claims, No Drawings FOAMED REACTION PRODUCT OF A RESOLE WITH A SULFONATED NOVOLAC BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to phenol-formaldehyde resins and particularly, though not exclusively, to such resins which can be used in the production of resin foams, eg for use as insulating materials.

2. Description of the Prior Art In co-pending US. Pat. Application Ser. No. 123851 filed Mar. 12 1971, certain phenol-formaldehyde resins are described and claimed comprising the product of reaction of 1 part by weight of a composition produced by reacting a phenol with concentrated sulphuric acid in the ratio 0.8 to 1.5 moles of sulphuric acid per mole of the phenol, and then adding per mole of the phenol a quantity of formaldehyde in the range having a lower limit of 0.3 moles and an upper limit of 0.8 moles when per mole of the phenol in the presence of a basic catalyst.

SUMMARY OF THE INVENTION It is a main object of the present invention to porvide improved phenol-formaldehyde resins for use as insulating materials.

According to the present invention we provide a phenol-fornuildehyde resin comprising the product of reacting a sulphonated novolac resin, which has been condensed from at least one phenol and formaldehyde and subsequently sulphonated so as to contain sulphonic acid groups, with a resole resin.

Some of the sulphonic acid groups of the resin can be neutralised to give a sulphonate metal salt or can be reacted with an organic base.

The invention also includes the method of producing a phenol-formaldehyde resin comprising condensing a novolac resin from at least one phenol and formaldehyde, sulphonating the novolac resin so that it contains sulphonic acid groups, and reacting the sulphonated novolac resin with a resole resin.

in this Specification, the terms novolac resin" and resole resin are used in accordance with the following definitions.

A novolac resin is a resin produced from 1 mole of a phenol or a mixture of phenols and not more than 1 mole of an aldehyde or mixture of aldehydes, at a pH not greater than 7, the resin being characterised in that it ISIII'I a thermoplastic condition and hardenable by treatment with a cross-linking agent, and is further characterised in that polymeric chains present in the resin have ends which do not contain hydroxymethyl or substituted hydroxymethyl groups. A resole resin is a resin produced from a phenol or mixture of phenols and an aldehyde or mixture of aldehydes in the presence of an alkaline catalyst (the molar proportion of aldehyde being not normally less than the molar proportion of phenol) characterised in that it contains hydroxymethyl or substituted hydroxymethyl groups.

Although the precise formulation of the composition resulting from the reaction of a phenol with sulphuric acid and subsequent addition of formaldehyde, as described in U.S. Pat. Application No. l23,85l is not known, it is believed to be distinctly different from that of the sulphonated novolac resin used in the present invention, which has essentially been condensed from a phenol and formaldehyde and subsequently sulphonated so as to contain sulphonic acid groups.

The condensation of the novolac resin may be effected in the proportions of 1 mole of the phenol or phenols to between 0.3 and 1.0 moles formaldehyde in acid conditions. Preferably the condensation is effected in the presence an organic acid. The organic acid may be oxalic acid, for example.

The sulphonation of the novolac resin is preferably effected by reaction of the condensed novolac resin with sulphuric acid in the proportion of 0.] to l.5 moles of sulphuric acid to l mole of the phenol or phenols used to form the novolac resin. 98% sulphuric acid may be used, and the sulphonation is preferably carried out at a temperature not exceeding l50C.

Preferably the viscosity of the product of the sulphonation is adjusted by dilution with water to a value of less than 100 poises at 20C, before reaction with the resole resin, the preferred value of the viscosity being less than poises at 20C.

The reaction between the sulphonated novolac resin and the resole resin is preferably carried out using an aqueous dispersion of the resole resin resulting from the condensation of at least one phenol and formaldehyde in the presence of an alkaline catalyst.

The resole resin is preferably condensed from at least one phenol and formaldehyde in the presence of an alkaline catalyst, in the proportions of l to 3 moles formaldehyde to 1 mole of the phenol used to form the resole resin.

It is of considerable assistance in mixing the sulpho nated novolac resin and the resole resin if their viscosities, before reaction, are of the same order of magnitude. Dilution of the sulphonation product and the condensation of the resole resin are therefore preferably carried out with this end in view.

The molar proportions in which the sulphonated novolac resin and the resole resin are reacted may vary widely, from to l 100, the preferred range of proportions lying between 20 l and l 20. When the resole content is low, e.g. with proportions between lOO l and 20 l, a cross-linking agent may be added to the reaction mixture.

To produce a solid foam, a surfactant and a foaming agent may be added to the reaction mixture of the sulphonated novolac resin and the resole resin. Alternatively surfactants and foaming agents may be added to either resin or to both resins or may be added at the resin mixing stage.

The surfactant may be a silicone oil and the foaming agent may be a low boiling aliphatic hydrocarbon or a halogenated derivative of such a hydrocarbon. The exothermic heat produced during the reaction may be used to activate the foaming agent.

DETAILED DESCRIPTION OF THE INVENTION The invention is particularly suitable for the production of new phenol-formaldehyde resin foams which can be used, for example, as fire-resistant insulating materials.

The examples now to be described are essentially produced by first forming a novolac resin by condensing phenol with formaldehyde in molar proportions of between 1 v: 0.3 and l 1.0 in the presence of between 0.008 and 0.025 moles oxalic acid, though other catalysts such as zinc acetate or mineral acids may be used. This reaction is known. Generally it is intitated by heatphonated by reaction with from 0.1 to 1.5 moles of 98% sulphuric acid at a temperature between 100 and 150C for 30 to 60 minutes, finally diluting the resultant product with water to adjust its viscosity. Table l ing the mixture to between 75C and 110C, wheregives Examples Al to A23 of sulphonated novolac resupon the exothermic reaction usually causes a further ins produced in this manner, showing the solids content temperature rise. The reaction may be continued for and viscosity of the diluted product. The viscosity between one/fourth hour and 2 hours according to the should be less than 100 poises at 20C and preferably materials used and the temperature maintained. The less than 80 poises. The formaldehyde used may be at reaction mixture containing the condensed novolac least partly in its polymerised form of purat'ormalresin is then cooled to between 60 and 75C and suldehyde (abbreviated as p.f.a. in Table 1).

TABLE 1 Com- Phenol Formul- Acid Catalyst Conden- Cool 98% Sulphonution Moles Solids Viscosity po- (moles) dehyde (Oxalic Acid sation Resin H- ,SO. Time and Water '7' (poises an silion (moles) x ep here Time and To (moles) Temperature added to 2o(; No. stated other- Temp. "(I ad ust wise) Viscosity (moles) Al 1 phenol 0.6 0.02 100C 0.54 100-120C 1.94 64.11 12 (3754 for 1 for 30 Formulinl hr. minutes A2 1 phenol 0.6 0.02 100C 70 0.6 110-135C 3.3 7 .5 16

for 80 for 40 min. minutes A3 1 phenol 0.6 0015 110-130C 60 0.8 135C for 2 74.3 30

(1:77: for 65 lgltgtci nptes .a.) min. or p minutes A4 1 phenol 0.5 0.023 110-120C 70 0.4 110-130C 5.6 511 5 (82% for for 30 p.141.) mm. minutes A5 1 phenol 0.4 0.01 110-100C 60 0.5 100-120C 5.6 74.7

(87% for 120 for 60 .1111.) min. minutes A6 I phenol 0.6 0.01 100- 60 0.6 120C for 2.11 75.0 28.6

(82% (Zinc Acetate) 110C mmules pin.) for 120 min. A7 1 phenol 0.6 0.016 100C 60 0.3 120C for 3.5 68.7 83

(8771 for 30 40 minutes p.f.a.) min. A11 1 phenol 0.7 0.015 110-105C 70 0.5 115-120C 3.0 69.3 51

(82% for for 30 7.1.21.) min. minutes A) 1 phenol 0.11 0.015 JO-110C 65 0.4 120C for 2.8 62.3

(142) for 15 30 minutes x1111.) min. .-\10 l phenol I 0.6 0.015 110-110C 0.1 120C for 1.4 66.0 411.3

(82"; for 15 30 minutes 1.1.11.1 min. .\11 1 phenol 0.6 0.016 100C 70 0. 110-130C 2.8 60 39 ($79 for 30 for 30 .l'.-.\.) min. minutes A12 1 phenol 0.7 0.015 85C for 60 0.7 125130C 2.8 67.3 15

(82% 60 min. for 40 .1111.) minutes A13 1 phenol 03 002 85C for 0.6 120C for 2.8 69.3 10

(112% 60 min. 45 minutes .f.zi.) A14 1 phenol 06 0.012 85C for 1 130C for 2.11 35 (8271 90 mm. 30 minutes p.1.:1.) A15 1 phenol 0.7 0.012 -90C 70 1.5 120130C 2.8 72 1 1 (8271 for for 35 .f.u.) min. minutes A16 1 phenol 0.9 0.008 75C for 70 0.4 120C for 4.2 5 .11 15 6 (8271 60 mm. 30 minutes xfiu.) A17 1 phenol I 1.0 0,016 xii-90C 75 0.3 120C for 5.6 40.3

(11271 for 90 30 minutes m.) 0 70 x 2 0. 25 80C f)|' 70 0.6 C for 1.7 A111 1 phcll l 32 0 60 30 minutes A O 70 5 70 0.012 75C for 70 0.3 150 for 2.8 Al) 1 phenol (212.2702 60 mm 30 mmucs 1.1111.) A20 0.5 I 0.7 0.012 110C for 65 0.5 110C for 2.11 57.4 18

phenol (82)? 60 min. 30 mlnules 0.5 p.l'.:l.1 I A21 11.5 0.7 0.012 75C for 60 0.25 125C for 4.0 53.2 31

phenol (112 21 45 min. 30 mlnutes 0.5 p.111) 1 A22 p 0 131 0.55 0.015 75C l'or 60 0.27 115C for 5.5 60.1 111.

phenol (X251 60 min. 30 minutes (1.09 p.f.a.l resorei- TABLE 1 Continued Com- Phenol Formal- Acid Catalyst Conden- Cool 9871 Sulphonation Moles Solids \iscosin P- (moles) dehyde (Oxalic Acid sation Resin H 50, I Time and Water )1 (poises zit sition (motefi) except where Time and To (m l Temperature added to C 1. No. stated other- Temp. C adjust wise) Viscosity (moles) A23 075 0.7 0.012 75C for 60 0.3 120C for 5.5 48.0 1 1.2

phenol (X271 60 min. minutes 0.25 pfa.) m-cresol IN Example Al the reaction product of phenol and formalin (the novolac resin), instead of being cooled,

kaline catalyst, e.g. barium hydroxide or sodium hydroxide. After the condensation, the mixture has its pH was concentrated by evaporation under reduced pres- 15 adjusted with sulphuric acid to a pH of preferably sure until the product had a solids content of 79% and a viscosity of 360 poises at 20 C. Then the concentrated resin was mixed with 0.54 moles of 98% sulphuric acid and the sulphonation reaction proceeded as set out in Table 1.

about 7. In practice it has been found convenient to operate between pH 6 and pH8.

Table 11 shows Examples B1 to B9 of the production of such a resole resin, with the solids content and vis- 20 cosity of the products.

TABLE I1 Com- Phenol Formalin Paraformaldehydc Total Alkaline Condensation Solids Viscosil) po- (moles) (37% 1 (moles) Formaldehyde Catalyst Time and "/1 (poises) sition oles) (moles) (moles) Temperature at 20C) No.

B1 1 phenol 0.08 2.38 (8792) 2.46 0.02 2% hrs. C 76 13 Ba(OH) 2 hr. C I .hrs. C B2 1 phenol 0.08 1.62 (8771) 1.7 0.02 2 hrs. 43C 611 12 BatOH): 2 hrs. 63C

1 hrsv 71C 113 1 phenol 0.08 1.149 (87%) 1.97 0.04 2 hrs. -,46C 68.5 70

NaOH 2 hrs. 60C

l hr. 50 mins. 74C 114 l phenol 300 3.00 0.02 2%: hrs. 60C 73.3 27

NaOH add urea 0.5

mole 1 hr. 75C 1 hrs. C concentrate by evaporation under reduced pressure. B5 1 phenol 3.00 (8271) 3.00 0.01 1% hrs. C 71.2 12

NaOH B6 1 phenol 1.00 (82%) 1.00 0.02 2% hrs. 85C 782 NaOH B7 {0.5 phenol) 2.00 (8271) 2.00 0.0125 1 hr. 55C 73.) 35.2

0.5 o-cresol NaOH 1 /2 hrs. 65C 1 hr. 75C B8 05 phenol 2.00 (827:) 2.00 0.0125 1%. hrs. 55C 717 10.0

0.5 m-cresol NaOH 2 hrs. 65C

1 hr. 75C B9 0.5 phenol 2,00 (8271) 2.00 0.0125 1 hr. 55C 61.6 3.4

0.5 p crcsol NaOH 1% hrs. 65C 1 hr. 75C

In the above examples, except Example A1, it has been found convenient to cool the reaction product before sulphonation, but such a step is not an essential one.

In some cases, it may be desirable to neutralise some of the sulphonic acid groups in the sulphonated novolac, to give a sulphonate metal salt, or to react some of. them with an organic base.

It will be seen that the viscosities of the resole resins in Table 11 range from 3.4 to 35.2 poises at 20C and are of the same order of magnitude as those of the sulphonated novolac resins of Table 1. This greatly facilitates the mixing of these resins for producing the desired resin foam.

The molar proportions in which the resins may be mixed (with the addition of the surfactant and the foaming agent) to produce the foams varies widely. Table 111 shows 41 Examples, identified as F1 to F41, of the mixing of various examples of sulphonated novolac resins (A2 to All and A13, A14 and A15 from Table l) with examples of resole resins (B1 to B6 from Table 111) in proportions ranging from 1 to 1 100. A preferred range of proportions, giving foams with good fire-resistant properties, is from 20 l to 1 20.

7 8 TABLE 111 Further particulars of the production of foams Fl to F I A] B] H FM M +83 :5 F27 A8 +8 :2 F41, and of eleyen further foams identified as F42 to 2 A2 3| 5 A4 53 m; F2 9 B1 5 F52, are set out in Table IV which shows the nature and F3A3+B11z1 F16A4+B3115U F29A9 +B120:1 F 4 A3 BI 12 H7 A4 B3 M F30 A9 Bl 50:1 amount in parts by we|ght of the sulphonated novolac, F 5 A3 31 1:3 A5 33 1:20 F31 A9 Bl 100:1 5 resole, surfactant and foaming agent used in each case. F6A3+B12:1 F19 A5+B3 1:33 F32Al0-1-B1 1:1 1 F 7 A3 B2 :9 F20 A6 B3 m F33 All B3 MOO together with the reaction temperature and the density F 11 A3 +132 150 F21 A6+B3 m0 F34 A6 +31 10:1 0 t e resultant foam- E?) 12.31% 1:28 221g: 2:} 22 i3: When the resole content is low as in Example F29. F11 A3 B2 F24 A6 Bl F37 A3 +85 1:4 F and F31, a cross-linking agent for example hexa- F12 A4 B3 1.10 F25 A7 Bl 2:1 F38 A3 B6 3 /21 10 methylene tetramme IS preferably added. This may also F13 A4 33 H0 F26 A7 M 532513? be added, as in Example F38, when the proportion of F4| A15 formaldehyde in the resole 1S relatively low.

TABLE IV Com- (Parts Resole 1 Parts Parts Foaming (Parts Reaction Resultant p o N by by Surfactant by Agent by Temperature Foam Density 11011 weight) weight) weight) weight] C (lb/cult) Fl A1 411 B1 411 Silicone 1.7 Arcton 1 1 12 411 2.2

Y 6252 F2 A2 411 B1 Silicone 1.7 Arcton 1 1 12 15 1.)

Y 6252 F3 A3 25 B1 25 Silicone (1.7 Arcton 1 1 6 15 5.7

Y 6252 F4 A3 17 B1 34 Silicone 11.7 Arcton 1 1 6 411 2 (1 Y 6252 F5 A3 13 BI 39 Silicone 11.7 Arcton 1 1 4 41) 2 M Y 6252 Arcton 113 2 F1 A3 34 B1 17 Silicone (1.7 Arcton 11 6 l5 1 1 Y 6252 F7 A3 5 B2 Silicone l Arcton 1 l 4 um Y 6252 Arcton 113 2 F11 A3 1 B2 511 Silicone 1 Arcton 1 13 4.7 65 1.84

Y 6252 F9 A3 1 B2 511 Silicone 1 Hexane 4 (r5 1 0 Y 6252 F111 A4 1 B3 511 Silicone 1 Arcton 1 l b 211 2 h L 5321) F1 1 A3 1 B2 211 Silicone 11.4 Arcton 1 13 4 811 I 1 1. 53211 1"12 A4 1 113 111 'l'ween 411 (1.3 n-pentane 1.25 (:11 2.11 F13 A4 1 B3 111 'l'wecn 411 (1.3 npentune 2.7 on 11.7 [-14 A4 5 I13 25 Silicone 11.7 n-pentane 2.5 1111 2. 1

1. 5321) 1-1 5 A4 3 113 24 'lween 411 11.7 n-pentane 2.5 (11) 4 F11 A4 11.5 B3 25 Silicone 11.5 n-pentane 3 (111 11.7

1. 5321) F17 A4 1125 B3 25 Silicone 11.5 Hexane 2.5 65 11.7

L 53211 FIR A5 1.5 B3 311 Silicone 1.3 Arcton 1 1 4 6(1 1.11

L 53211 Arcton 113 2 Fl) A5 1.5 B3 511 Silicone 1.5 Arcton 1 13 5 11111 2.11

L 5321) F211 A11 25 B3 25 Silicone 11.7 Arcton 1 13 7 411 2.7

l. 5321) F21 A11 3 B3 311 Silicone 11.9 npentane 5.5 65 2.1

L 5321) F22 A6 311 B1 111 Tween 41) 11.7 Arcton 1 1 7 411 2.4 F23 A1 411 B1 111 Tween 40 (1.9 Arcton 1 1 8 411 2.11 F24 A11 25 B1 5 Tween 41) (1.7 Arcton 1 1 3 411 3.2 F25 A7 32 B1 16 Silicone (1.7 Arcton 1 1 5 211 1.11

L 5321) F211 A7 25 B1 25 Silicone 11.7 Arcton 1 1 5 21) 2.9

L 5321) F27 A8 1611 B1 321) Silicone 9 Arcton 1 1 5(1 211 2.7

L 5320 F211 A) 111 B1 511 Silicone 2 Carbon 5 811 2.3

L 53211 tetrachloride F29 A) 311 B1 1.5 Tween 41) (1.9 Arcton 1 13 7 811 15 treated with hexamethylene tetramine .2 F311 A) 25 111 (1.5 'lween 411 (1.5 Arcton 1 13 b 1111 2.7

treated with hexnmethylene tetrmnine 1 F31 A) 25 B1 (1.25 Tween 41) (1.5 Arcton 1 13 6 81) 3.2

treated with hexamethylene TABLE IV Continued (omv v I (Parts Resole (Parts I I Parts Foaming (Parts Reaction Resultant ma Mimi gf {P ,h) w b Agent Temp erature Foanr Dcnsit} .NO I 5 (f g \\'Clghl) C (lb/cult.)

tetramine 1 F32 A 25 B1 25 Silicone 0.7 Arcton l 1 4 2,1

L 5320 +Arcton 113 2 F33 A1 1 0.25 B3 Silicone 0.8 Benzene 2.5 110 2.2

L 5320 sulphonyl hydrazide F34 A6 B1 3 Tween 40 0.9 n-pentane 5.5 (10 2.5 F A9 25 B3 25 Silicone 0.7 Arcton l 1 7 20 2.5

L 5320 F36 A6 25 B4 25 Silicone 0.7 Arcton l l 5 20 2.

L 5320 F37 A3 10 B5 Silicone 1.5 Arcton l l 7 60 2.5

L 5320 F38 A3 70 B6 20 Silicone 2 Arcton 1 13 12 20 8.1

treated L 5320 hardened at with 100 Ca(OH) 2.5 and hexamethylene tetramine F39 A13 25 B3 25 Silicone 0.7 Arcton l l 5 20 7.1)

L 5320 F40 A14 1 1 B1 Silicone l Arcton l 1 6 0.0

L 5320 F-ll A15 5 Bl 50 Silicone 0.8 Arcton l 1 7 60 5.)

L 5320 F42 A16 25 B3 25 Silicone 0.7 Arcton l l 8 20 4.2

L 5320 F43 A17 3-1 B3 17 Silicone 0.7 Arcton l l X 60 5.0

L 5320 l"-l-l Alla 18.7 B3 411 Silicone I Arcton l 10 20 2.0

lrcaletl l. 5320 Arcton 113 5 with (a0 I..l l--l5 Al) 25 ll] 25 Silicone 0.7 Arcton l l X 20 3.3

l. 5320 1 11 A20 25 ll} 25 Silicone 0.7 Arcton l l 5 20 2 I l. 5320 ["47 All 25 B3 25 Silicone 0.7 Arcton l l 5 20 5.4

L 5320 F48 A22 32 I33 lo Silicone 0.7 Arcton l l 5 20 3.1 4

L 5320 1 -10 A23 3 B3 16 Silicone 0.7 Arcton l l 5 20 3.8

L 5320 F50 A111 25 B7 25 Silicone 0.7 Arcton l l 5 -1 3.8

L 5320 F51 AIX 5 B8 25 Silicone 0.7 Arcton l l 5 20 5.1

l. 5320 F52 A18 2 B9 25 Silicone 0.7 Arcton l l 5 20 1.8

The surfactants identified in Table IV as Silicone Y 6252 and Silicone L 5320, are Silicone oils. Tween 40 is a polyoxyethylene sorbitan monopalmitate manufactured by Honeywill-Altas.

The foaming agent Arcton 1 1 is CCl F, and Arcton 1 13 is CFCL CF CL both made by LG]. Limited.

What is claimed is:

l. A foamed phenol-formaldehyde resin comprising the product of condensing at least one phenol with formaldehyde in proportions of 1 mole phenol to not more than 1 mole formaldehyde, at a pH not greater than 7, to form a novolac resin, subsequently sulphonating the novolac rcsin so as to incorporate sulphonic acid groups therein, and reacting said sulphonated novolac resin with a resole resin in the presence of a surfactant and a foaming agent to form said solid foam.

2. A foamed resin according to claim 1, wherein the sulphonated novolac resin contains sulphonic acid groups which have been neutralized to give a sulphonate metal slat, or have been reacted with an organic base.

3. A foamed resin according to claim I, wherein the condensation of the novolac resin has been effected in the proportions of 1 mole phenol to between 0.3 and 1.0 moles formaldehyde in acid conditions.

4. A foamed resin according to claim 3, wherein the condensation has been effected in the presence of an organic acid.

5. A foamed resin according to claim 4, wherein the organic acid is oxalic acid.

6. A foamed resin according to claim 1 produced by a process wherein the sulphonation of the novolac resin is effected by reaction of the condensed novolac resin with sulphuric acid in the proportion of 0.1 to 1.5 moles of sulphuric acid to l mole of the phenol used to form the novolac resin.

7. A foamed resin according to claim 6 produced by a process wherein the sulphonation is carried out using 98% sulphuric acid.

8. A foamed resin according to claim 7, produced by a process wherein the sulphonation is carried out at a temperature not exceeding 150C.

9. A foamed resin according to claim I, produced by a process wherein the viscosity of the product of the sulphonation is adjusted by dilution with water to a value of less than 100 poises at 20C, before reaction with the resole resin.

10. A foamed resin according to claim 9, produced by a process wherein the said viscosity is adjusted to less than poises at 20C.

11. A foamedresin according to claim 1, wherein the resole resin has been condensed from at least one phenol and formaldehyde in the presence of an alkaline catalyst, in the .proportions of l to 3 moles formaldehyde to 1 mole of the phenol resin.

12. A foamed resin according to claim 1, produced by reacting the sulphonated novolac resin and the resole resin in molar proportions of between 100 l and l 100.

13. A foamed resin according to claim'2, wherein the said proportion lies between 20 l and l 20.

14. A foamed resin according to claim 2, produced by reacting the sulphonated novolac resin with the resole resin in molar proportions of between 100 l and 20 l, with the'addition of a cross-linking agent.

15. A foamed resin according to claim 1, wherein the surfactant is a silicone oil.

16. A foamed resin according to claim 1, wherein the foaming agent is a lowing boiling aliphatic hydrocarbon.

17. A foamed resin according to claim 1, wherein the foaming agent is a halogenated derivative of a low boiling aliphatic hydrocarbon.

18. A method of producing a foamed phenolformaldehyde resin, comprising the step of condensing at least one phenol and formaldehyde, in proportions of 1 mole phenol to not more than 1 mole formaldehyde at a pH not greater than 7 to form a novolac resin, sulphonating said novolac resin so that it contains sulphonic acid groups, and

reacting said sulphonated novolac resin with a resole resin the presence of a surfactant and a foaming agent, to form a solid foam.

19. A method according to claim 8, wherein a portion ofthe sulphonic acid groups in the sulphonated novolac resin are neutralized to give a sulphonate metal salt. or are reacted with an organic base.

20. A method according to claim 18, wherein the condensation of the novolac resin is effected in the proportions of 1 mole phenol to between 0.3 and 1.0 moles formaldehyde in acid conditions.

21. A method according to claim 20, wherein the condensation is effected in the presence of an organic acid.

22. Amethod according to claim 2], wherein the organic acid is oxalic acid.

23. A method according to claim 18, wherein the sulphonation of the novolac resin is effected by reaction used to form the resole of the condensed novolac resin with sulphuric acid in the proportion of 0.1 to 1.5 moles of sulphuric acid to 1 mole of the phenol used to form the novolac resin.

24. .A method according to claim 23, wherein the sulphonation is carried out using 98% sulphuric acid.

25. A method according to claim 24, wherein the sulphonation is carried out at a temperature not exceeding 150C.

26. A method according to claim 18, wherein the viscosity of the product of the sulphonation is adjusted by dilution with water to a value of less than 100 poises at 20C before reaction with the resole resin.

27. A method according to claim 26, wherein the said viscosity is adjusted to less, than poises at 20C.

28. A method according to claim 18, wherein the reaction between the sulphonated novolac resin and the resole resin is carried out using an aqueous dispersion of the resole resulting from the condensation of at least one phenol and formaldehyde in the presence of an alkaline catalyst.

29. A method according to claim 18, wherein the resole resin is condensed from at least one phenol and formaldehyde in the presence of an alkaline catalyst, in the proportions of l to 3 moles formaldehyde to 1 mole of the phenol used to form the resole resin.

30. A method according to claim 18, wherein the viscosity of the sulphonated novolac resin and of the resole resin, before reaction, are of the same order of magnitude.

31. A method according to claim 18, wherein the sulphonated novolac rsin and the resole resin are reacted in molar proportions of between l and l 100.

32. A method according to claim 31, wherein the said proportions lie between 20 l and l 20.

33. A method according to claim 31, wherein the said proportions lie between 100 l and 20 l and a crosslinking agent is added to the reaction mixture.

34. A method according to claim 18, wherein the surfactant is a silicone oil.

35. A method according to claim 18, wherein the foaming agent is a low boiling aliphatic hydrocarbon.

36. A method according to claim 18, wherein the foaming agent is a halogenated derivative of a low boiling aliphatic hydrocarbon.

37. A method according to claim 18, wherein the exothermic heat of the reaction is used to activate the foaming agent. 

1. A foamed phenol-formaldehyde resin comprising the product of condensing at least one phenol with formaldehyde in proportions of 1 mole phenol to not more than 1 mole formaldehyde, at a pH not greater than 7, to form a novolac resin, subsequently sulphonating the novolac resin so as to incorporate sulphonic acid groups therein, and reacting said sulphonated novolac resin with a resole resin in the presence of a surfactant and a foaming agent to form said solid foam.
 1. A FOAMED PHENOL-FORMALDEHYDE RESIN COMPRISING A FOAMED PRODUCT OF CONDENSING AT LEAST ONE PHENOL WITH FORMALDEHYDE
 2. A foamed resin according to claim 1, wherein the sulphonated novolac resin contains sulphonic acid groups which have been neutralized to give a sulphonate metal salt, or have been reacted with an organic base.
 3. A foamed resin according to claim 1, wherein the condensation of the novolac resin has been effected in the proportions of 1 mole phenol to between 0.3 and 1.0 moles formaldehyde in acid conditions.
 4. A foamed resin according to claim 3, wherein the condensation has been effected in the presence of an organic acid.
 5. A foamed resin according to claim 4, wherein the organic acid is oxalic acid.
 6. A foamed resin according to claim 1 produced by a process wherein the sulphonation of the novolac resin is effected by reaction of the condensed novolac resin with sulphuric acid in the proportion of 0.1 to 1.5 moles of sulphuric acid to 1 mole of the phenol used to form the novolac resin.
 7. A foamed resin according to claim 6 produced by a process wherein the sulphonation is carried out using 98% sulphuric acid.
 8. A foamed resin according to claim 7, produced by a process wherein the sulphonation is carried out at a temperature not exceeding 150*C.
 9. A foamed resin according to claim 1, produced by a process wherein the viscosity of the product of the sulphonation Is adjusted by dilution with water to a value of less than 100 poises at 20*C, before reaction with the resole resin.
 10. A foamed resin according to claim 9, produced by a process wherein the said viscosity is adjusted to less than 80 poises at 20*C.
 11. A foamed resin according to claim 1, wherein the resole resin has been condensed from at least one phenol and formaldehyde in the presence of an alkaline catalyst, in the proportions of 1 to 3 moles formaldehyde to 1 mole of the phenol used to form the resole resin.
 12. A foamed resin according to claim 1, produced by reacting the sulphonated novolac resin and the resole resin in molar proportions of between 100 : 1 and 1 :
 100. 13. A foamed resin according to claim 2, wherein the said proportion lies between 20 : 1 and 1 :
 20. 14. A foamed resin according to claim 2, produced by reacting the sulphonated novolac resin with the resole resin in molar proportions of between 100 : 1 and 20 : 1, with the addition of a cross-linking agent.
 15. A foamed resin according to claim 1, wherein the surfactant is a silicone oil.
 16. A foamed resin according to claim 1, wherein the foaming agent is a low boiling aliphatic hydrocarbon.
 17. A foamed resin according to claim 1, wherein the foaming agent is a halogenated derivative of a low boiling aliphatic hydrocarbon.
 18. A method of producing a foamed phenol-formaldehyde resin, comprising the step of condensing at least one phenol and formaldehyde, in proportions of 1 mole phenol to not more than 1 mole formaldehyde at a pH not greater than 7 to form a novolac resin, sulphonating said novolac resin so that it contains sulphonic acid groups, and reacting said sulphonated novolac resin with a resole resin in the presence of a surfactant and a foaming agent, to form a solid foam.
 19. A method according to claim 8, wherein a portion of the sulphonic acid groups in the sulphonated novolac resin are neutralized to give a sulphonate metal salt, or are reacted with an organic base.
 20. A method according to claim 18, wherein the condensation of the novolac resin is effected in the proportions of 1 mole phenol to between 0.3 and 1.0 moles formaldehyde in acid conditions.
 21. A method according to claim 20, wherein the condensation is effected in the presence of an organic acid.
 22. A method according to claim 21, wherein the organic acid is oxalic acid.
 23. A method according to claim 18, wherein the sulphonation of the novolac resin is effected by reaction of the condensed novolac resin with sulphuric acid in the proportion of 0.1 to 1.5 moles of sulphuric acid to 1 mole of the phenol used to form the novolac resin.
 24. A method according to claim 23, wherein the sulphonation is carried out using 98% sulphuric acid.
 25. A method according to claim 24, wherein the sulphonation is carried out at a temperature not exceeding 150*C.
 26. A method according to claim 18, wherein the viscosity of the product of the sulphonation is adjusted by dilution with water to a value of less than 100 poises at 20*C before reaction with the resole resin.
 27. A method according to claim 26, wherein the said viscosity is adjusted to less than 80 poises at 20*C.
 28. A method according to claim 18, wherein the reaction between the sulphonated novolac resin and the resole resin is carried out using an aqueous dispersion of the resole resin resulting from the condensation of at least one phenol and formaldehyde in the presence of an alkaline catalyst.
 29. A method according to claim 18, wherein the resole resin is condensed from at least one phenol and formaldehyde in the presence of an alkaline catalyst, in the proportions of 1 to 3 moles formaldehyde to 1 mole of the phenol used to form the resole resin.
 30. A method according to claim 18, wherein the Viscosity of the sulphonated novolac resin and of the resole resin, before reaction, are of the same order of magnitude.
 31. A method according to claim 18, wherein the sulphonated novolac resin and the resole resin are reacted in molar proportions of between 100 : 1 and 1 :
 100. 32. A method according to claim 31, wherein the said proportions lie between 20 : 1 and 1 :
 20. 33. A method according to claim 31, wherein the said proportions lie between 100 : 1 and 20 : 1 and a cross-linking agent is added to the reaction mixture.
 34. A method according to claim 18, wherein the surfactant is a silicone oil.
 35. A method according to claim 18, wherein the foaming agent is a low boiling aliphatic hydrocarbon.
 36. A method according to claim 18, wherein the foaming agent is a halogenated derivative of a low boiling aliphatic hydrocarbon. 